It is known to vaporize heating oil by application of vaporization energy and to subsequently mix with combustion air. However, complete vaporization of the heating oil requires relatively high boiling temperatures, which cause formation of cracking products. These cracking products comprise primarily cokes, which deposit in the vaporization chamber and are difficult to remove.
My earlier patents, U.S. Pat. No. 4,486,362 and corresponding German Patent DE-PS 31 22 770, further disclose vaporization of liquid fuel in a stream of heated combustion air. Using this method, the fuel can be transferred into the combustion air at significantly lower temperatures. These temperatures, for heating oil, are on the order of half the maximum boiling temperature of the liquid fuel. However, the heating oil reacts with oxygen in the combustion air to form long-chain hydrocarbons which no longer vaporize in the combustion air at the aforementioned low temperature level. Thus, even according to this method, there remains an unprocessible oil residue.